Pipetting device having two temperature sensors

Abstract

The invention is in the field of automatic analysis devices and relates to a heatable pipetting device for an automatic analysis device and a method for providing a reaction mixture. The pipetting device comprises a pipetting needle having two temperature sensors at different distances to the tip of the pipetting needle.

What is claimed is: 
     
       1. A pipetting device comprising:
 a pipetting needle having a tip and having a first temperature sensor at a small distance from the tip of the pipetting needle and a second temperature sensor at a greater distance from the tip of the pipetting needle, 
 a heating device for heating the pipetting needle, and 
 a controller for regulating heat generation by the heating device, 
 wherein the first temperature sensor is connected to the controller and the second temperature sensor is not used by the controller to regulate heat generation by the heating device. 
 
     
     
       2. An automatic analysis device having at least one pipetting device as claimed in  claim 1  and an automatically movable or pivotable transfer arm, wherein the at least one pipetting device is fastened on the automatically movable or pivotable transfer arm. 
     
     
       3. The automatic analysis device as claimed in  claim 2  having multiple receptacle positions for receiving reagent vessels and having multiple receptacle positions for receiving reaction vessels and having at least one measurement unit for measuring a physical property of a reaction mixture, wherein the analysis device further comprises a control unit configured to control a method for providing a reaction mixture of a liquid to be analyzed and at least one reagent liquid in a reaction vessel, the method comprising:
 heating the pipetting needle of the pipetting device; 
 aspirating a volume of a reagent liquid into the heated pipetting needle; 
 moving the pipetting needle to a desired location for dispensing of the aspirated volume of the reagent liquid into a reaction vessel; then 
 measuring a temperature using the first temperature sensor and a temperature using the second temperature sensor; 
 comparing the temperature measured by the first temperature sensor to a predefined minimum temperature and a predefined maximum temperature; and 
 establishing that the temperature measured by the first temperature sensor either:
 exceeds the predefined maximum temperature, or 
 does not exceed the predefined maximum temperature and does not fall below the predefined minimum temperature, or 
 falls below the predefined minimum temperature, 
 
 wherein if it is established that the temperature measured by the first temperature sensor exceeds the predefined maximum temperature or falls below the predefined minimum temperature, the aspirated volume of the reagent liquid is dispensed from the pipetting needle and then disposed of. 
 
     
     
       4. The automatic analysis device as claimed in  claim 3 , wherein the control unit is further configured so that if it is established that the temperature measured by the first temperature sensor does not exceed the predefined maximum temperature and does not fall below the predefined minimum temperature, the method further comprises:
 ascertaining the absolute temperature difference between the temperature measured by the first temperature sensor and the temperature measured by the second temperature sensor; 
 comparing the ascertained temperature difference to a predefined maximum temperature difference value; and 
 establishing that the ascertained temperature difference is either:
 greater than the predefined maximum temperature difference value or 
 less than or equal to the predefined maximum temperature difference value, 
 
 wherein if it is established that the ascertained temperature difference is greater than the predefined maximum temperature difference value, the aspirated volume of the reagent liquid is dispensed from the pipetting needle and then disposed of. 
 
     
     
       5. The automatic analysis device as claimed in  claim 4 , wherein the control unit is further configured so that if it is established that the ascertained temperature difference is less than or equal to the predefined maximum temperature difference value, the method further comprises:
 dispensing the aspirated volume of the reagent liquid from the pipetting needle into the reaction vessel, 
 supplying the reaction vessel having the reaction mixture to a measurement unit, and 
 measuring a physical property of the reaction mixture in the measurement unit.